Item printing system

Abstract

An item printing system for printing imprints on moving items, comprising: an item transport path through which items are in use transported in a transport direction; an item transport unit for transporting items through the item transport path; a printing unit ( 11 ) for printing imprints on items transported through the item transport path; a free roller ( 27 ) driven by respective items transported through the item transport path; and a speed measurement unit for measuring speed of rotation of the free roller, wherein the measured speed of rotation of the free roller is utilised to provide relative control of printing by the printing unit and speed of transport of items by the item transport unit.

1. An item printing system for printing imprints on moving items, comprising:
 an item transport path through which items are in use transported in a transport direction; 
 an item transport unit for transporting items through the item transport path; 
 a printing unit for printing imprints on items transported through the item transport path; 
 a free roller driven by respective items transported through the item transport path; 
 a speed measurement unit for measuring speed of rotation of the free roller; and 
 a control unit for controlling rate of printing by the printing unit in response to the measured speed of rotation of the free roller. 
 
   
   
     2. The system of  claim 1 , wherein the free roller comprises a fixed roller. 
   
   
     3. The system of  claim 1 , wherein the free roller comprises a floating roller biased towards the item transport path. 
   
   
     4. The system of  claim 1 , wherein the item transport unit comprises a drive roller assembly comprising the free roller and a driven roller disposed opposite the free roller, which rollers act to engage an item and transport the same along the item transport path. 
   
   
     5. The system of  claim 4 , wherein the driven roller comprises a fixed roller. 
   
   
     6. The system of  claim 4 , wherein the driven roller comprises a floating roller biased towards the free roller. 
   
   
     7. The system of  claim 1 , wherein the speed measurement unit comprises a tachometer unit for measuring speed of rotation of the free roller, the tachometer unit including an encoder wheel coupled to the free roller. 
   
   
     8. The system of  claim 1 , wherein the items comprise mail items. 
   
   
     9. An item printing system for printing imprints on moving items, comprising:
 an item transport path through which items are in use transported in a transport direction; 
 an item transport unit for transporting items through the item transport path: 
 a printing unit for printing imprints on items transported through the item transport path, wherein the printing unit comprises first and second print heads spaced in the transport directions; 
 a free roller driven by respective items transported through the item transport path; 
 a speed measurement unit for measuring speed of rotation of the free roller; and 
 a control unit for controlling rate of printing by the printing unit in response to the measured speed of rotation of the free roller. 
 
   
   
     10. An item printing system for printing imprints on moving items, comprising:
 an item transport path through which items are in use transported in a transport direction; 
 an item transport unit for transporting items through the item transport path; 
 a printing unit for printing imprints on items transported through the item transport path; 
 a free roller driven by respective items transported through the item transport path, wherein the free roller is disposed upstream of the printing units; 
 a speed measurement unit for measuring speed of rotation of the free roller; and 
 a control unit for controlling rate of printing by the printing unit in response to the measured speed of rotation of the free roller. 
 
   
   
     11. An item printing system for printing imprints on moving items, comprising:
 an item transport path through which items are in use transported in a transport direction; 
 an item transport unit for transporting items through the item transport path; 
 a printing unit for printing imprints on items transported through the item transport path; 
 a free roller driven by respective items transported through the item transport path; 
 a speed measurement unit for measuring speed of rotation of the free roller; and 
 a control unit for controlling speed of transport of mail items by the item transport unit in response to the measured speed of rotation of the free roller. 
 
   
   
     12. The system of  claim 11 , wherein the free roller comprises a fixed roller. 
   
   
     13. The system of  claim 11 , wherein the free roller comprises a floating roller biased towards the item transport path. 
   
   
     14. The system of  claim 11 , wherein the item transport unit comprises a drive roller assembly comprising the free roller and a driven roller disposed opposite the free roller, which rollers act to engage an item and transport the same along the item transport path. 
   
   
     15. The system of  claim 14 , wherein the driven roller comprises a fixed roller. 
   
   
     16. The system of  claim 14 , wherein the driven roller comprises a floating roller biased towards the free roller. 
   
   
     17. The system of  claim 11 , wherein the speed measurement unit comprises a tachometer unit for measuring speed of rotation of the free roller, the tachometer unit including an encoder wheel coupled to the free roller. 
   
   
     18. The system of  claim 11 , wherein the items comprise mail items. 
   
   
     19. An item printing system for printing imprints on moving items, comprising:
 an item transport path through which items are in use transported in a transport direction; 
 an item transport unit for transporting items through the item transport path; 
 a printing unit for printing imprints on items transported through the item transport path, wherein the printing unit comprises first and second print heads spaced in the transport directions; 
 a free roller driven by respective items transported through the item transport path; 
 a speed measurement unit for measuring speed of rotation of the free roller; and 
 a control unit for controlling speed of transport of mail items by the item transport unit in response to the measured speed of rotation of the free roller. 
 
   
   
     20. An item printing system for printing imprints on moving items, comprising:
 an item transport path through which items are in use transported in a transport direction; 
 an item transport unit for transporting items through the item transport path; 
 a printing unit for printing imprints on items transported through the item transport path; 
 a free roller driven by respective items transported through the item transport path, wherein the free roller is disposed upstream of the printing units; 
 a speed measurement unit for measuring speed of rotation of the free roller; and 
 a control unit for controlling speed of transport of mail items by the item transport unit in response to the measured speed of rotation of the free roller. 
 
   
   
     21. An item printing system for printing imprints on moving items, comprising:
 an item transport path through which items are in use transported in a transport direction; 
 an item transport unit for transporting items through the item transport path; 
 a printing unit for printing imprints on items transported through the item transport path; 
 a free roller driven by respective items transported through the item transport path; and 
 a speed measurement unit for measuring speed of rotation of the free roller, wherein the measured speed of rotation of the free roller is utilised to provide relative control of printing by the printing unit and speed of transport of items by the item transport unit. 
 
   
   
     22. An item printing system for printing imprints on moving items, comprising: an item transport path through which items are in use transported in a transport direction;
 an item transport unit for transporting items through the item transport path; 
 a printing unit for printing imprints on items transported through the item transport path, wherein the printing unit comrrises first and second print heads spaced in the transport direction; 
 a free roller driven by respective items transported through the item transport path; and 
 a speed measurement unit for measuring speed of rotation of the free roller, wherein the measured speed of rotation of the free roller is utilised to provide relative control of printing by the printing unit and speed of transport of items by the item transport unit. 
 
   
   
     23. An item printing system for printing imprints on moving items, comprising:
 an item transport path through which items are in use transported in a transport direction; 
 an item transport unit for transporting items through the item transport path; 
 a printing unit for printing imprints on items transported through the item transport path; 
 a free roller driven by respective items transported through the item transport path, wherein the free roller is disposed upstream of the printing unit; and 
 a speed measurement unit for measuring speed of rotation of the free roller, wherein the measured speed of rotation of the free roller is utilised to provide relative control of printing by the printing unit and speed of transport of items by the item transport unit.